532 , 0« the PciviT of eleBrlcal Batteries. 



Experiment 8, with four jars, two removed. Two inches of the fame fort of wu'C was placed 

 In the circuit, all the jars remaining as in the laft experiment, the machine put in motion, 

 till B begun to afcend, then two of the jars were drawn away ; the difcharge was caufed, 

 and the wire was fufed, and run into balls. 



Repeated with the fame fort of wire i\ inches long, the difcharge caufed it to be red hot 

 the whole length. 



Experiment 9, tulth fourteen jars. Wire of to^ part of an inch diameter was taken, eight 

 inches long, and proceeded according to Experiment 7 ; ,it was fufed and run into balls. 



Experiment lo, ■with fourteen jars, feven ranoved. Two inches of the fame fort of wire was 

 ■taken, and proceeded with, according to Experiment 8 j it was fufed and run into balls. 



The refult of the foregoing experiments proves fufhciently, that double quantities of elec- 

 tric fluid, in the form of a difcharge, will melt four times the length of wire of a certain dia- 

 meter; and Experiments 5 and 6 prove that when one-third part is added to two, three times 

 the length of wire was fufed. 



Thefe experiments give reafon to apprehend fome error in Dr. van Marum's experiments, 

 becaufe he found his batteries to increafe in power only in the fame proportion as the coated 

 furface was increafed, viz. that double furface of coated glafs only could fufe double lengths 

 of wire of the fame diameter. 



The doctor might, perhaps, have "been led into a miftake in the following manner : firft, he 

 rnay not have charged the batteries to an equal height, £s he did not, at that time, poflefs an 

 electrometer of fuilicient accuracy for that purpofe ; and, fecondly, he may not have been 

 aware -of the different degrees of fufion caufed by eleftric difchargeSj but only judged of the 

 force by the wires being converted into balls ; by which great miftakes may happen. For 

 if a wire be taken i S inches long, and of fuch a diameter, that when a jar or battery is 

 charged to fuch a height as juft to caufe it to run into balls, much fliorter lengths of that 

 fame fort of wire may be fubje^bed to the fame force, and ftill be only converted into balls by 

 it ; eveii if only feven inches were taken, nothing but bidls will appear ; the only difference 

 will be, that the balls will be fmaller, and difperfed to a greater dillance, which might be ea- 

 fily overlooked. If fix inche* of the fame fort of wire be taken, it will be converted into 

 balls and flocculi, or brown oxyde of iron -, fo that to be accurate in this point, the loweft 

 degree of fufion mull be had, which is known when the charge has pafled, by the wire being 

 f-een red-hot the whole length, and afterwards run into balls. 



Having now fufficiently proved by experiment, in what proportion different quantities of 

 eledtric fluid act upon different lengths of wire, which was required to be known, in order 

 to explain in what proportion the charging capacity of a jar or battery is incrcafcd by breath- 

 ing into it, before the charging begins, I Hiall proceed in the next place to explain this point. 

 The opinion that I had at firft entertained (though fupported by Dr. van Marum's experi- 

 ments), that I had found out a method of increafing the charging capacity of batteries to 

 three times thairufual farce, was not fupported by the fa£ts that the ufual power of a clean and 

 dry battery, containing 17 fquare feet coated furface, namely, that of fufing from 18 to 2Z 

 inches of iron wire of -^'^^ part of an inch in diameto", will be increafed by breathing into 

 tliejar, fo as to become capable of fufing 60 inches. If the firft-mcntioned effed be taken at 



a mean 



